Remote control device for multiplespeed gear boxes



June 9, 1953 F. D'ozoUvlLLE 2,641,637

REMOTE CONTROL DEVICE FOR MULTIPLE-SPEED GEAR BOXES 4 Sheets-Sheet l Filed March 13 1950 II mi June 9, 1953 F. D'ozouvlLLE 2,641,637

REMOTE CONTROL DEVICE FOR MULTIPLE-SPEED GEAR BOXES Filed March 13. 1950 4 Sheets-Sheet 2 6k, 1T" g4.

Hlm hg June 9, 1953 F. DozoUvlLLE 2,641,637

REMOTE CONTROL DEVICE FOR MULTIPLE-SPEED GEAR BOXES Filed March 13, 1950 4 Sheets-Sheet 5 June 9, 1953 F. DozoUvlLLE 2,641,637 v REMOTE CONTROL DEVICE FOR MULTIPLE-SPEED GEAR BOXES Filed March 13. 1950 v 4 Sheets-Sheet 4 Patented June 9, 1953 REMOTE CONTROL DEVICEy FOR MULTIPLE- SPEED GEAR BOXES Franois dOzouville, Paris, France, assignor to Siper S. A., Emsallah, Tangier, a corporation of the Tangier Zone Application March 13, 1950, Serial No. 149,364. In Switzerland March 29, 1949A (Cl. F75-335) 11 Claims.

The present invention relates to a remote control device for a multiple-speed gear-box of the type comprising at least one sliding member arranged to actuate sliding gears to bring them selectively into engagement with at least one chosen gear wheel.

In lthe remote control device according to the invention, this sliding member is actuated by at least one electro-magnet. By energizing one of these electro-magnets, a longitudinal movement of the sliding striker ro'd is' obtained, which is thus brought into a position corresponding to one of the chosen gear-ratios.

The sliding member, consisting of a striker rod, may be locked in working position by energizing another electro-magnet, called the locking electro-magnet, or, on the contrary, by interrupting the energizing circuit of this electro-magnet.

This control device enables omitting the usual gear-box control lever which, in the case of a motor car, obstructs the space between the two front seats.

In addition, this device enables the remote control in the cases when the gear-box mechae nism is at a distance, and this without employing a complicated gear device, as is the case with certain mechanical control devices.

The accompanying drawing shows, by way of example, two embodiments of the remote control device according to the invention:

Fig. lis a partial sectional elevation of this embodiment.

Fig. 2 is the electro diagram of Vthis embodiment, arranged for providing five gear-ratios, one of which is a reverse speed.

Fig. 3 is a cross section of a modiedl form of the electric locking mechanism.

Fig. 4 is a sectional elevation, along 4 4 in Fig. 5, of the upper part of a gear-box of a motor vehicle.

Fig. 5 is a horizontal section along 5-5 in Fig 44.

Fig. 6 is a sectional elevation along YI-I in Fig. 4. A

Fig. '7 is a sectional elevation valong I-'I in Fig. 5.

Fig. 8 and. Fig. 9 are detail views showing ac'-l tuating cams for the switch ofthe device, and

Fig. 10 is the electric diagram of this device.

In Fig. 1, I is a sliding striker rod consisting of a tube having a variable magnetic cross se'cV tion, 2 is the armature of the electro-magnet 3, 4 are springs serving to bring the striker rod back to its dead position when the electro-magnets are not energized, 5 are bosses of the 'casing' of 'the gear-box forming the gear-box mecha# Cal nism, in which the striker rod I is slideably mounted. The tubular ends of this striker rod may be provided with slots into which the ends of screws secured to the casing penetrate, so as to prevent the rod from rotating about its axis. The ends of the rod I carry push-pieces serving to actuate contacts 8. 9 and I0 are a striker fork and a sliding gear. I I is an electro-magnet which has an armature I2 and serves to lock the striker rod inthe chosen working position. To this end the armature I2 carries a projecting part I3, in the form of a spur, arranged to engage into notches I4 provided in the striker rod. I 5 is a spring serving to draw back the armature I2 when the electro-magnet II is not energized through a selector arranged to send the current through one or the other of the electro-magnets 3.

In Fig. 2, I6 is' a source of electric current, for instance the battery of accumulators of a motor vehicle on which the control device is mounted. The main switch II of this vehicle also sends current to a selector comprising the switches I8 and I9. The switch I8 has three positions: forward, contact point 20; reverse, contact point 25 and neutral, contact point O. The switch I9 has four positions 2'I, 22, 23' and24 corresponding to fourdi'ie'rent forward gear-ratios. The windings 3 of the electro-magnets and II of the lockying electro-magnet are fed through this selector I8--I9 and they are connected to the mass through the change-over switch 8 in such a manner that only one of these windings 3 and II can be energized at a time.

The device described operates in the following manner:

To obtain a determined gear-ratio, the switches I8 and I9 are actuated so as to energize that one of the electro-magnets 3 which corresponds to this gear-ratio. The armature 2 of a striker rod moves to the corresponding working position and causes its sliding gear to mesh with the gear wheel corresponding to the desired ratio. At the end ofthe stroke, the contact 8` is actuated, the

circuit of the electro-magnet 3 is interrupted and that of the locking electro-magnet II is closed. The projecting part I3 penetrates into that one of the notches I4 which corresponds to the chosen ratio and thus locks the striker rod in the position corresponding to this ratio. It is to be noted that the electro-magnet II is fed through the selector when the latter is no longer in its dead position.

When the selector is brought back to its dead position, the electro-magnet II is no longer en-y ergized and the armature l2 is pushed back by the spring i5, thus releasing the striker rod. The latter then moves under the action of the springs d until the forces exerted by these springs balance one another, the striker rod then being in its neutral position.

It is to be remarked that the electro-magnetA il can be constructed so as to have a very small current consumption. On the other hand, the spring li enables an improved operation of an auto-synchronizing device. Indeed, its action is opposed to that of the electro-magnet 3 and, at

the end of the stroke, this spring tends to slow and which can thus lock any one of three striker.

rods in one of its working positions. If desired, this electric locking mechanism may also be arranged to lock simultaneously the other striker rods in their respective dead positions: it sufces to provide each striker rod with a notch cooperating with one of the balls in the dead position of this rod. The springs may also be substituted by rigid push-pieces, formed by distance-pieces secured to the member I3,

On Figs. 4 to 7, the drawing shows the cover Si of a gear-box of afmotor vehicle. Sliding members 32 and 33, which form the striker rods of this gear-box, are mounted in the cover 3l. Each of these rods bears a striker fork 3d, respectively 35, designed to move the sliding gears of the second and third speeds and of the first and reverse speeds of the gear-box respectively.

Each of the rods is actuated by an electromagnet with double winding 35, respectively 3l. Each of these electro-magnets has a movable core of ferro-magnetic material 38, 39 supported inside the windings by rods 40, lli arranged to slide in bosses forming part of the cover 3i. Springs 42, are lodged inside the hollow rods 4U, respectively di and bear against the core 38 at one end, and against pins 44 at the other. These pins are fixed in the bosses of the cover 3i and slide in longitudinal slits d5 of the rods 40, respectively lil. The springs 42 thus maintain the core 38 in a central position as long as no current is flowing in either of the windings of the associated electro-magnet- One of the rods 4B, respectively 4i is connected to the sliding member 32, respectively 33 by an arm lil, respectively l, fixed to this member and having a trunnion 19, respectively 53, which passes through the corresponding hollow rod di), respectively lil. The electro-magnet 36 has two windings 5l and 52 wound on a bobbin 53 made of insulating material. This bobbin is suspended in the cover 3l by disks 54 having central holes through which the corresponding rod 40 passes freely and, on their outer faces, centering surfaces by means of which the bobbin 53 and the disks 54 are centered with respect to guiding bearings provided in the cover 3| for the rod Ml. The disks 5 are each provided on their inner face with a cylindrical ange supporting the bobbin 53. They are made of ferro-magnetic material and also serve to improve the magnetic circuit of the electro-magnet. This magnetic circuit comprises the core 38, the rod All), an air-gap sepaonehand and of the core 5i) on the other.

rating this rod 49 from the disk 54, and this disk itself, the cylindrical flange of which surrounds the end of the core 38 at a small distance. When an electric current is flowing in one of the windings 5D or 5l, the core 33 is attracted inside the cylindrical iiange` of the adjacent disk 54, thus tending to reduce the reluctance of the magnetic circuit. It may be noted in this connection, that the cover 3l and its bosses are generally made of non-magnetic material, such as cast aluminium or an alloy of aluminium `and magnesium. The electro-magnet 31 is constructed in the same way as the electro-magnet 35 and also comprises disks 55, each of which has a centering projection on its outer face and a cylindrical flange on its inner face. This electro-magnet also has two windings 56 and 5l, wound on a bobbin 58 of insulating material.

When one of the cores 38 is displaced under the action of an electric current flowing through one of the associated windings 5i and 52, respectively 55 and 51, it moves the associated sliding member 32, respectively 33 by reason of its mechanical connection swith this member by means of the hollow rod d, respectively 4|, the trunnion iig, respectively 5U and the arm 4l, respectively 48. In its turn, the sliding member moves the associated sliding gears by means of the fork 34, respectively 35 and causes them to engage with the chosengear wheel. r

A locking electro-magnet 55, which can b seen in Fig. 4 and in Fig. '7, is arranged at one end of the device. This electro-magnet has a core 6i), and a winding 6i and an outer screenv t2 made of magnetic material. The core 60 bears a plate 53, also made of magnetic material and the diameter of which is equal to that of the magnetic screen 52. It is arranged to slide. `inside the winding `and has a cylindrical projecting part 54 of small diameter, which passes freely through the lower end of the screen 62. When electric current flows through the winding Si), the projecting part 5d is pressed against a plate 65 which, in its turn, presses von two balls 65 (Figs. 4 and 7), so as to lock the two sliding members '.52 and 34 in position. These balls are guided in holes bored in a boss of the cover 3i in which the members 32 and 33 are slideably mounted. The balls 65 engage in V- shaped notches of these sliding members. When the electro-magnet 59 is not energized, the balls 65 are free to move upwards, pushed back by one of the inclined flanks of one of the notches of one of the said members, which are thus free to slide and to bring the associated sliding gears into engagement with the chosen gear wheel. The magnetic screen 62 serves to improve the magnetic circuit of the electro-magnet 59. This magnetic circuit consists of this screen on the A slight air-gap subsists between the projecting part 64 of this core and a central hole in the bottom of the casing 62, and a variable air-gap separates the Yplate 53, secured to the core E0, from the upper edge of the screen 62. When electric current ilows in the winding 5|, the core is attracted downwards, its plate 63 coming nearer to the edge of the screen 62, thus reducing the reluctance of the magnetic circuit. It must be noted that the balls 65 are not pressed by springs, the weight of the plate 65, added to that of the core 60, being suicient to maintain them in their respective holes. Owing to the favorable layout of its magnetic circuit, and

toA the, fact that. there is no force acting against -the magnetic attraction ofV the core 60, the electro-magnet 59 may be arranged so as t-o draw a very small amount of electric energy.

Av switch B1, preferably of the sudden-interrupting type, serves to control the electro-magnet 5.9,. This switch can particularly be seen on Fig. 5 and on Fig.V 6. It is controlled by cams. 68 (Fig 8) and 68 `(Fig. 9) respectively actuated by one of the hollow rods 4B and by one of the rods 4I. These cams are arranged to bear on a rollerl when brought-into a position corresponding to one of the working positions of the associated sliding member. The roller 10 is secured to the end of a resilient arm 1i, de- Signed tQrpresS Qn a Qontrol-button 12 of the. Switch B1. The cams 68. and 63 respectively are rotatably mounted on a rod 13 secured to the cover ofthe gear-box. They each comprise an arm provided with a slot surrounding a projecting part of the end vof the trunnion -49 or 5.0 of'the arm 41, respectively 48 of the associated sliding member 32, respectively 33.

As may be seen in Fig. 7, a locking device is provided to prevent the two sliding members 32 and 33 from moving simultaneously. This device comprises a pin 14 lodged in the cover 3| and arranged between the sliding members 32 andV 33. This pin is pointed at both ends. It can slide transversally between the sliding members 32 and 33 to engage notches of these members. The length of the pin 14 `is such that, when one oi the sliding members 32 or 33 is displaced, `one of the inclined flanks of the notch Of this member in which the point of the pin 14 was engaged pushes this pin back and presses it into the opposite notch of the other sliding member, so as to look this other member in posi tion.

The device operates in a very simple manner. A selector consisting of a switch with four positions, enables to select any one of the four working positions of the gear-changing mechanism (Fig. 10). When the movable contact of this switch is moved from one positi-on to another, for instance from its position III, corresponding to the third speed, to its position II, corresponding to the second speed, the energizing circuit of the electro-magnet 5I of the locking electromagnet 6I isinterrupted, and the core 3B is broughtback to its central position by the springs 4,2. The gear-changing mechanism is then in its dead position, and the clutch of a vehicle tted with this mechanism must then be actuated.. When the movable contact of the switch reaches the contact point II,` the winding 52 of the electro-.magnet 35 is energized, Whilst the winding 6I of4 the Ylocking electro-magnet 5S is not, this winding being short-circuited by the switch 61, which is then closed, no pressure being applied to the button 12. This winding 52 attracts the core 38, thus` bringing the sliding member 32 to its position corresponding to the second speed. When this member reaches this position, the associated cam `68 presses on the roller 1B until the resilient arm 1I is brought into contact with the button 12 of the switch61 and depresses it, thus opening the switch. The winding 6i of the locking electro-magnet is then immediately energized through the winding 52 of the actuating electro-magnet, with which it is connected in series. The pedal of the clutch may then be released, the gear-changing operation being completed.

The casing aand cover ofthe gear-box-might also be madeof magnetic material, such as cast iron; it would bev `sufficient to provide bushings of non-magnetic material to accommodate the hollow rods 40, respectively 4|, which carry the cores 38. The disks 54-and 55, the plate 63 and the magnetic screen 62, as well as the cores 38, arepreferably made of soft steel.

It may be noted that the arrangement of the switch 61 is extremely advantageous, because, the interruption-spark, which tends to be producedwhen the current energizing one of the actuating electro-magnets is interrupted by this switch, is for a `great part absorbed by Ythe winding 6|, connected in parallel with the switch 61,

The striker rod can be made 0f. any magnetic 0r non-magnetic material. @f .metal 0r of, plastic. material for instance..

The described remote control device can be ap: plied to any *numberl of gear-ratios and of slide. ing gears.

The described looking mechanism could be ree placed by any other Vknown electric, mechanical, pneumatic or hydraulic device operating, as that of the described device, only after the striker rod has been brought to one of its working posi! tions. The locking action may be controlled by the electro-magnet actuating the sliding gears. In that case,` a `mechanical control of the locking action may be obtained, which has theadvantage of ensuring that the sliding gears which are in mesh and those which are in their dead positions are all correctly positioned. To this end, the control electro-magnet which has brought a sliding gear in engagement may be left energized, a resistance beingv connected in series with this electro-magnet when the desired position has been reached. The reduced current which then flows through the winding of this elecro-magnet is suicient to provide. a satisfactory locking action.

The second embodiment of the device is particularly simple -and reliable and effective in operation.

TheseoontrolV devices are suitable for motor cars and also for all, kinds of motor vehicles and of machine-tools comprising multiple-.speed gearboxes.

The gear-box control lever which, in the case of a motor car, obstructs Vthe space between the two front seats, can be Asubstituted by asimple electric switch capable of controlling the gearbox mechanism at a distance without employing a complicatedgear-device, even when this mechanism is far oil from the switch.

What I claim is:

l. An operating arrangement for a device e. g., a gear adapted to be moved into and out of operative position by a sliding member comprising, in combination, an operating member; means for slidably mounting said operating member between inoperative position and operative position; rst electromagnet means associated with said slidable operating member for sliding the same from inoperative position into operative position; a first energizing electric circuit connected to said first electromagnet means for energizing the same for movement of said slidable operating member` from inoperative into operative position; blocking means associated with said slidable operating member movable between inoperative position permitting free sliding ot said slidable operating member and operative position engaging and blocking said slidable operating member so as to prevent sliding thereof; second electromagnet means associated with said blocking means for moving the'same from an inoperative position into operative position; a second energizing electric circuit connected to said second electromagnet means for energizing the same for movement of said blocking means into operative position; and switch means actuated by said slidable operating member when the same reaches its operative position and, upon actuation, connecting said second energizing electric circuit so as to energize said second electromagnet means, moving said blocking means into operative position and thus holding said slidable operating member in its operative position.

2. An operating arrangement for a device e. g., a gear adapted to be moved into and out of operative position by a sliding member comprising, in combination, an operating member; means for slidably mounting said operating member between inoperative position and operative position; first electromagnet means associated with said slidable operating member for sliding the same from inoperative position into operative position; a first energizing electric circuit connected to said rst electromagnet means for energizing the same for movement of said slidable operating memberA from inoperative into operative position; blocking means associated with said slidable operating member movable between inoperative position permitting free sliding of said slidable operating member and operativeposition engaging and blocking said slidable operating member so as to prevent sliding thereof; second electromagnet means associated with said blocking means for moving the same from an inoperative position into operative position; a second energizing electric circuit connected to said second electromagnet means for energizing the same for movement of said blocking means into operative position; and switch means actuated by said slidable operating member when the same reaches its operative position, and upon actuation, disconnecting said first energizing electric circuit so as to terminate further energization of said first electromagnet means and simultaneously connecting said second energizing electric circuit so as to energize said second electromagnet means, moving said blocking means into operative position and thus holding said slidable operating member in its operative position.

' 3. An operating arrangement for a device e. g, a gear adapted to be moved into and out of operative position by a sliding member comprising, in combination, an operating member; means for slidably mounting said operating member between inoperative position and operative position; first electromagnet means associated with said slidable operating member for sliding the same from inoperative position into operative position; a nrst energizing electric circuit connected to said rst electromagnet means for energizing the same for movement of said slidable operating member from inoperative into operative position; blocking means associated with said slidable operating member movable between inoperative position permitting free sliding of said slidable operating member and operative position engaging and blocking said slidable operating member so as to prevent sliding thereof; second electromagnet means associated with said blocking means for moving the same from an inoperative position into operative position; a second energizing electric circuit @negated to seid. Second vei160e@,freenet insane.

`for energizing the same for movement of said blocking means into operative position; and a' contact breaker switch connected in said second energizing electric circuit and parallel to said second electromagnet means, said contact breaker switch being actuated by said slidable operating member when the same reaches its operative position and, upon actuation, connecting said second electromagnet means in said second electric energizing circuit so as to energize said second electromagnet means, moving said blocking means into operative position and thus holding said slidable operating member in its operative position.

4. An operating arrangement for a device e. g., a gear adapted to be moved into and out of operative position by a sliding member comprising, in combination, an operating member; means for slidably mounting said operating member between inoperative position and operative position; first electromagnet means associated with said slidable operating member for sliding the same from inoperative position into operative position; a iirst energizing electric circuit connected to said rst electromagnet means for energizing the same for movement of said slidable operating member from inoperative into operative position; blocking means associated with said slidable operating member movable between inoperative position permitting free sliding of said slidable operating member and operative position engaging and blocking said slidable operating member so as to prevent sliding thereof; second electromagnet means associated with said blocking means for moving the same from an inoperative position into operative position; a second energizing electric circuit connected to said second electromagnet means for energizing the same for movement of said blocking means into operative position; and a contact breaker switch connected in said second energizing electric circuit and parallel to said second electromagnet means, said contact breaker switch being actuated by said slidable operating member when the same reaches its operative position and, upon actuation, connect- 'ing said second electromagnet means in said second electric energizing circuit so as to energize said second electromagnet means, moving said blocking means into operative position and thus holding said slidable operating member in its operative position, said iirst and second electric circuits being connected in series with each other whereby the current flowing through said rst electromagnet means is substantially reduced by the impedance of said second electromagnet means when said slidable operating member reaches the operative position thereof.

5. An operating arrangement for a device e. g., a gear adapted to be moved into and out of operative position by a sliding member comprising, in combination, an operating member; means for slidably mounting said operating member between inoperative position and operative position; rst electromagnet means associated with said slidable operating member for sliding the same from inoperative position into operative position; a iirst energizing electric circuit connected to said rst electromagnet means for energizing the same for movement of said slidable operating member from inoperative into operative position; blocking means associated with said slidable operating member movable between inoperative position permitting free sliding of said slidable operating member and operative position engaging and .9 blocking said 'slidable bperating' member so as to prevent sliding thereof; ksecond. `electromagnet means associated with said 'blocking means -for moving the same from4 an inoperative position into operative position; a second energizingelectric circuit connected to said second Velectromagnet means for energizing the same-for movement of said blocking means into operative position; a Contact breaker switch connected in 'saidsecond energizing electric circuit and parallel tcsaid second electromagnet means; and mechanical transmission means actuating -said contact breaker switch when said Vvslidabl'e*A operating member reaches its operative position, `said Vcon'- tact breaker switch, upon actuation, connecting said second electromagnet means in said second electric energizing circuit Yso as to energiz/esaid second electromagnet means, 'movingsaid blocking'means into operative position and thus holding said slidable operating member in its operative position. r M

6. An operating arrangement for a device e. g., a 'gear adapted to be Vmoved into V'and out of operative positicn'by a 'sliding member comprising, in combination, anoperating member; means for slidably mounting said operatingmember between inoperative position and operative position; rst electromagnet means associated with said Asiidabieoperatirig member'ror sliding the same from inoperative position into operative position; a nrst energizing electric circuit connected Jto-,said rstelectromagnet means for energizing` the same forinovement of said slidable operatnigumember from `inoperative into operative position; blocking meansl associatedk with saidV slidable operating member movable between inoperative positionupermitting free sliding of said slidable operating member and operative position engaging and blocking said slidable Operating member so asto prevent sliding thereof; second electromagnetV means associated with said blocking means for moving the same from an inoperative position in to operative position; a second energizing electriccircuit connected to said secondV electromagnet-,means for energizing the same for movementof said blocking means into operative position; a contact breaker switch connected in said second energizing electric circuit and parallel to said second electromagnet means; and mechanical transmission means actuating said contact breaker switch when said slidable operating member reaches its operative position, said contact breaker switch, upon actuaton, connecting said second electromagnet means in said second electric energizing circuit so as to energize said second electromagnet means, moving said blocking means into operative position and thus holding said slidable operating member in its operative position1 said first and second electric circuits being connected in series with each other whereby the current flowing through said rst electromagnet means is substantially reduced by the impedance of said second electromagnet means when said slidable operating member reaches the operative position thereof.

'7. A multiple speed gear box comprising at least one sliding member having at least one working position and `adapted for actuating sliding gears so as to bring the same selectively into engagement with at least one gear wheel, a separate actuating electromagnet for each working position of each sliding member, each of said electromagnets being adapted to actuate the associated sliding member for bringing it into a Vcorresponding working position, a single latching electromagnet adaptedy to actuate atleast one latching member movable transversally to anV associated sliding member for latching the same in any selectedworking position, and at least one switch arranged to be actuated by at least one associated-sliding member for interrupting at least a nainjer'i'ergizingv circuit for ana'ctuating electromagnet associatedwith this sliding member when the same reaches the working position corresponding to this electromagnet and to cause latchingof said lsliding member in this working positionvby'm/e'ans of the latching electromagnet and ofthe latching member cooperating with said sliding-member; l

8. A multiple speed gearbox 'comprising a plurality of sliding members having each at least 'one workingposition and each adapted for actuating sliding gears so asV to bring the same selectively and one at a time into 'engagement with at least one ygear Wheel; aQvjseparatej actuating electromagnet-for each workingrposition of each sliding member, each of said electromagnets being adapted toactuate the associated sliding member for bringing theh same into a corresponding working position, .a single latching electromagnet adapted to actuate 'aplurality vof latching members,` one for each sliding I'n'ernberV and each movable transversally to the associated sliding `member for latching the-same-l 'i'n any selected working position, all the latching membersbeing mechanically connected-to the armature Vof the'latching electromagnet, and atleast'oneL switcharranged to be actuated by at least one `'associated sliding member for interrupting atleast a main energizing ycircuit for an actuatingV electromagnet associated with thisv sliding member when vthe same reach-es the working position corresponding to this electromagnet and to cause latching of said sliding memberin this Working position by means of the latching electromagnet and of the latching .member cooperating with `said sliding member, whereby each'sliding memberis latched in each working position `by said 'latching electromagnet.

9.A` multiple'fspeed' gear box comprising at least one'sliding umember having at least one working position and adapted for actuating sliding gears so as to bring the same selectively into engagement with at least one gear wheel, a separate actuating electromagnet for each working position of each sliding member, each of said electromagnets being adapted to actuate the associated sliding member for bringing it into a corresponding working position, a single latching electromagnet adapted to actuate at least one latching member movable transversally to an associated sliding member for latching the same in any selected working position, and a contactbreaker switch connected across the coil of said latching electromagnet and arranged to be actuated by at least one associated sliding member for interrupting a main energizing circuit for an actuating electromagnet associated with this sliding mem-ber when the same reaches the working position corresponding to this electromagnet and to cause said latching electromagnet to be energized and to latch said sliding member in said working position by means of the latching member cooperating with said sliding member.

10. A multiple speed gear boX comprising at least one sliding member having at least one working position and adapted for actuating sliding gears so as to bring the same selectively into engagement with at least one gear wheel, a separate actuating electromagnet for each Working position of each sliding member, each of said electromagnets being adapted to actuate the associated sliding member for bringing it into a corresponding working position, a selector-switch adapted for selectively energizing any of said actuating electromagnets, a single latching electromagnet adapted to actuate at least one latching member movable transversally to an associated sliding member for latching the same in any selected working position, and a contact breaker switch connected across the coil of said latching electromagnet, in a main energizing circuit for the coils of all the actuating electromagnets, and arranged to be actuated by at least one associated sliding member for interrupting the main energizing circuit for any actuating electromagnet associated with this sliding member when the same reaches the working position corresponding to this electromagnet and to cause said latching electromagnet to be energized through the coil of this actuating electromagnet and to latch said sliding member in said working position by means of the latching member cooperating with said sliding member, whereby the current owing through the coil of any actuating electromagnet is substantially reduced by the impedance of the coil of the latching electromagnet connected in lseries therewith when the sliding member associated with said actuating electromagnet reaches the working position corresponding to this electromagnet.

11. A multiple speed gear box comprising a plurality of sliding members having each `at least yone Working position and each adapted for actuating sliding gears so as to bring the same selectively and one at a time into engagement with at least one gear wheel, a separate actuating electromagnet for each working position of each sliding member, each of said electromagnets being adapted to actuate the associated sliding member for bringing the same into a corresponding working position, a selector-switch adapted for selectively energizing any of said actuating electromagnets, mechanical interlocking means adapted to prevent more than vone sliding member being in a working position at the same time, a single latching electromagnet adapted to acl2 tuate at least onelatching member movable transversally to the sliding members for latching the same in any selected working position, a single contact breaker switch connected across the coil of said latching electromagnet, in a main energizing circuit for the coils of all the actuating electromagnets, and mechanical transmission means arranged to actuate said contact breaker switch from any of the sliding members for interrupting the main energizing circuit for any actuating electromagnet when the sliding member associated with this electromagnet reaches the working position corresponding to this actuating electromagnet and to cause said latching electromagnet to be energized through the coil of this actuating electromagnet and to latch said sliding member in said working position by means of the latching member cooperating with said sliding member, whereby the current flowing through the coil of any actuating electromagnet is substantially reduced by the impedance of the coil of the latching electromagnet connected in series therewith when the sliding member associated with Vsaid actuating electromagnet reaches the working position corresponding to this electromagnet.

FRANCOIS DOZOUVILLE.

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